In general, it is essential to generalize and downsize a light source when considering development of an X-ray pulse in the field of physical chemistry. However, targets used in approaches for generating X-ray pulses in the related art have been limited to metal foils or rare gas jets in a vacuum chamber. The present inventors have been conducting experiments for development and utilization of lasers instead of these targets for generating the X-ray pulses, which can be used under the atmospheric pressure.
We have already found that the fluorescence behavior of solid state organic molecules when using picosecond X-ray pulses generated from a photo-excitable X-ray tube and a laser as an excitation light has a characteristic element dependency in excitation of X-rays (Hatanaka et al, Summary of Lecture in Panel Discussion on Photochemistry, 2000, 2A29 (Sapporo, 2000)).